Allow a long description or note are to be added to the list, not individual items, so it persists rather than losing notes when I finish the task they're mapped to. Also easier to fit with Scott Belsky's Action Steps, Ref and Backburner method.

Limiting viewing context is, I think, a key feature in outlining. At the moment the 'hoisting' functionality is only half way there.

What I'd like to see is a simple, persistent way to maintain isolation/focus on one part of the hierarchy, and then navigate upwards / downwards through an easy shortcut, without having to use the '...' button (whose functionality I find quite confusing...).

I second the request for 'breadcrumbs' at the top.

Workflowy does this sort of thing really elegantly, although the rest of its feature set and general usability is nowhere near a match for checkvist.

Currently when you search or display due tasks, or search for tasks - the tasks hierarchy is flatten on the search page. It would be great to have an ability to view task hierarchy itself, because in my example I've a lot of similarly named tasks but in different hierarchies.

When in a design meeting, freeform editing like in Checkvist is very useful, but it's a lot of work to copy and paste Checkvist text into the issue tracker. Exporting directly from Checkvist would be awesome. The "highest level" task should be the issue title and the child tasks should be added to the issue description.

Exported tasks should be clearly marked and link to the corresponding Jira / Youtrack issue.

It would be great to have a calendar view of the current week (or day, or month) next to the checklist (where the keyboard hints are currently displayed) and being able to drag and drop tasks into the calendar.
This calendar view would be awesome to schedule your day and week based on your priority, and have a quick view on what needs to be done today.
If you couple that with Google Calendar integration and a full iphone app, you've got yourself the dreamiest organizational tool of all times!

I use the due dates to manage tasks across multiple lists. I worry that I may have missed adding a date to a task in one of my lists and, as a result, may never complete that item. It would be useful to have the ability to search across all lists for all items that do not have due dates assigned.